Apparatus for burning fire breaks in open grass country



A. J. BROAD Dec. 6, 1955 APPARATUS FOR BURNING FIRE BREAKS IN OPEN GRASSCOUNTRY 2 Sheets-Sheet 1 Original Filed Nov. 24, 1950 INVEMToR ARTHUJoHN 3R0 Dec. 6, 1955 J BROAD 2,725,875

APPARATUS FOR BURNING FIRE BREAKS IN OPEN GRASS COUNTRY Original FiledNov. 24, 1950 2 Sheets-Sheet 2 I Nl/ENToR ARTHUR Mu 3m) AG-EINTS UnitedStates Patent O APPARATUS FOR BURNING FIRE BREAKSJN OPEN GRASS COUNTRYArthur John Broad, Pyramid, Victoria, Australia Original applicationNovember 24, 1950, Serial No. 197,262. Divided and this applicationNovember 26, 1952, Serial No. 322,710

fllaims priority, application Australia November 28, 1949 3 Claims. (Cl.126-2713) burnt strips to check and prevent grass fires from,

spreading.

The present invention is directed to apparatus whereby a fire breakisburnt in an enclosure towed by a motor vehicle and into which isdirected a strong air current to support combustion sufiiciently inadvance of an extinguishing air current to enable a strip to be burntbefore the burning grass is put out by the extinguishing air current.

In the course of extended trials 1 have found that in order to beeffective, certain conditions, hereinafter fully explained, relating tothe flow and discharge of the extinguishing air current and thedisposition of igniting apparatus in the enclosure must be compliedwith, moreover, it has been found that for efiicient air discharge, theair flow from the generating blower or fan should be as short and directas possible.

Now the principal objective of this invention is the provision offirebreak burning apparatus of simple construction which is towed bya.powerdrivenvehicle so as to be traversed at relatively high speed overgrassed country to burn a fire break, as it travels.

A further object of the invention is to provide a fire break burningapparatus which is traversed by a power driven vehicle over the groundsurface, and forms therewith an enclosure wherein the grass is burnt tomake a fire-break as the apparatus travels, and which is speciallyadvantageous, though not exclusively adapted for use, in hot weather andstrong winds.

In achieving this further object and according to the invention, a firebreak burning apparatus to be towed by a power driven vehicle comprisesa horizontally disposed frame having tubular members for supplying waterto front and rear spray jets, a casing carried by the frame and open tothe ground at the bottom, transport wheels supporting the frame andeasing, a grass intake opening at the front of the casing, an airconduit flexibly connected with a power driven blower on the vehicle andpositioned centrally and longitudinally above the casing, air dischargenozzles connected with said air conduit and located at the front andrear of the casing, at least one burner mounted within the casing andsupplied with liquid fuel under pressure, flexible floating slidescarried at the sides of the casing and maintained in ground engagement,and a chimney or stack extending upwardly from the top of the casing fordischarge of products of combustion of grass burnt within the casing.

An illustrative apparatus in accordance with the invention for burningfirebreaks in open grass country is depicted in the accompanyingdrawings.

In these drawings:

Fig. 1 is a side elevation of the firebreak burning apparatus' whichisdispos'ed at the rear of andtowed by a motor vehicle.-

Fig. 2 is a plan of the firebreak illustrated in Fig. 1.

Fig; 3 is a. section on the line 33 of Fig. 1.

Referringfto these drawings in more detail, the. numeral 1 designatesgenerally a motor truck having mounted upon thetray thereofa centrifugalblower 2 of required capacity which is'drive-connected with a suitableengine or power plant 3, indicated diagrammatically in Fig. 2.

Upon'tlie' outlet of the blower 2. there is mounted a bend 4 which. isdirectedrearwardly as shown.

Connected to the.ou'tlet'of the bend 4 is a flexible air tube or conduit5 constructedof canvas or, the like.

The towed. firebreak' burning apparatus indicated generally by 74has'aframe 75 constructed of suitable metallic tubing, on which is secured asheet metal casing 76 closed at the top 77 'andopen at the bottom andhaving side and end walls.

The frame 75 andcasing '76 are carried upon transport burning apparatuswheels 78 and 79, the front wheels 78 being pivoted at 80 on the ends ofan axle 81 and connected by arms 82 and drag link 83 with a tow bar'8'4whereby the unit is connected to the rear of the truck 1.

The tow bar 84 is pivoted at "84a, and the'front wheels 78 are actuatedby'thetow bar so as to function as steering wheels in traversing bendsor corners.

To form an eifective ground seal at the sides of the casing 76 toprevent lateral spread of fire, there are provided plates or flaps 85which are guided for vertical movement and are free for groundengagement and to rise and fall in passing over inequalities in theground surface.

The plates 85may be raised clear of ground engagement as in traversingsharp corners, by lifting means manually actuate'd'from the truck trayand comprising operating bars 86 slidable in bearing brackets 87 securedto the upper tubular members 88 of the frame 75, bell crank levers 89and links 90.

The frame is provided with inner andouter parallel members 75a and 75bconnected by yo'kes a, and the plates b5 are guided for verticalmovement and maintained upright by'the spaced frame members 75a and 75bin traversing the ground surface, see Fig. 3.

The plates'85 are drawn over the ground surface by arms 91*v pivotedupon the'yokes 35a at 91a and connected by pins 92' to lugs 93 on theplates to which are also connectedthejlinks 90. g V The members ofthetubular frame 75 comprise conduits for water and are connectedby aflexible pipe'94 with a water pump 6 shown diagrammatically on'the trucktray.

Branch pipes 95 extend from the pipe 94 to the lower tubular members 96of the tubular frame 75, and the water is conducted through verticallydisposed members 97 of the frame to the upper members $8, the forwardends of which are fitted with water spray jets 98 While the rear endsare provided with connections 98a for hoses for manual use.

The flexible air conduit 5 is connected to an air tube 5 99 carried onthe firebreak burning apparatus 74 and divided into two branches 100 and101.

The branch 100 is extended to the rear of the unit and is provided witha fish tail discharge outlet or nozzle 102, which at the end is turnedinwardly at 103 into the casing 76 so as to direct the air flowforwardly therein.

The branch 101 is directed downwardly and is widened to comprise a fishtail nozzle 104', which at the lower end is turned inwardly at 105 todirect the air from the branch rearwardly into the casing 76.

Beneath the inturned end 105 there is a transverse opening in theforward end of the casing of suflicient height or width to provide anentrance for grass into the space within the casing 76, as the equipmenttravels. This space comprises a combustion chamber wherein the grass isburnt, ignition being effected by one or more burners 106 supplied withliquid. fuel through pipes as 107, connected with a fuel container 7under pressure on the truck.

Air to support combustion of the grass is supplied through the nozzles102 and 104, and smoke and products of combustion escape through achimney 108, which comprises a support for the air tube extension 99 andthe air tube branches 100 and 101. The chimney 108 is fitted with asuitable wire screen spark arrester not shown.

Internal baflies (not shown) are provided in the casing 76 to preventinterference by the inflowing air from the nozzles 102, 104 with thechimney draught, and air splitters (not shown) are provided in saidnozzles.

As the firebreak burning apparatus is towed by the truck 1, grass entersthe front of the combustion chamber through the transverse opening, andupon being ignited by the burner 106 is burnt within the former. Theground engaging plates or flaps confine the burning grass within thecombustion chamber and prevent ignition of grass external thereto.

Any grass not completely consumed is extinguished by the strong aircurrent entering the combustion chamber from the rear nozzle 102.

Spread of fire from the front end of the combustion chamber is preventedby the air blast entering the chamher from the front nozzle 104, whileany grass ignited externally to the chamber is extinguished by the watersprays emerging from the jets 98, and by means of water dischargedthrough 98a.

The firebreak burning apparatus above described may be arranged fortowing by a tractor in lieu of the truck 1, and in such an alternativearrangement, air blowers would hoses attached to the connections becarried at the front and rear of the apparatus and arranged to dischargeair through front and rear nozzles into the combustion chamber.

The air blowers may be driven by separate power plants or driveconnected with the power take-off of the tractor.

Such an alternative equipment would be provided with containers forliquid fuel for the burner 106 and water for jets 98 and hoseconnections 98a, the water being supplied by a power driven pump ashereinbefore described.

I claim:

1. An apparatus for burning firebreaks in open grass country, comprisinga powered vehicle, having mounted thereon a power-driven blower, watersupplying means and a container for liquid fuel; and a wheeled mobilefirebreak burning unit towed by the vehicle and including a rectangularframe having side members braced in parallel relation, front and rearwheels supporting the rectangular frame, towing means connecting theframe with the vehicle, an elongated bottomless casing mounted upon theframe and provided with a closed top, and side, front and rear walls toform with the underlying ground surface a combustion space and havingthe lower edge of the front wall spaced above ground level to form atransverse opening across the front of the casing for entry of herbageinto the casing to be burnt in the combustion space, a burner forigniting the herbage disposed within the front portion of the casing,flexible tubing connecting said burner with the liquid fuel container, aflexible air conduit extending rearwardly from the power driven blower,an air tube system connected to said air conduit and mounted on thecasing and including a first branch terminating in a rearwardly directednozzle positioned at the front of the casing to discharge air into thelatter to support combustion, a second rearwardly extended branch in theair tube system terminating in a forwardly directed nozzle positioned atthe rear of the casing to discharge air into the latter to extinguishincompletely burnt herbage, water spraying means incorporated in theframe, flexible tubing connecting said spraying means with the watersupplying means so that a water spray is emitted for quenchingsmouldering herbage, ground sealing means yieldably engageable with theground surface and supported by the frame at each side of the casing toprevent lateral spread of fire from said casing, and a chimney stack onthe casing for discharge of the products of combustion of the herbage.

2. An apparatus according to claim 1; wherein the rectangular frame iscomprised of tubular lateral frame sections having upper and lowerhorizontally disposed members connected by vertical members, saidtubular frame sections are connected by said flexible tubing with thewater supply means and carry said water spraying means.

3. An apparatus according to claim 1; wherein said ground sealing meansinclude vertically disposed guideways carried by the frame at the sidesof the casing, ground engaging plates pivotally connected to and guidedfor rising and falling sliding movements in said guideways, and manuallyoperable means for raising and maintaining the ground engaging platesabove and clear of the ground surface.

References Cited in the file of this patent UNITED STATES PATENTS531,648 'Risdon et al Jan. 1, 1895 1,112,241 Ward Sept. 29, 19141,458,070 Long et al. June 5, 1923 1,571,882 Belanger Feb. 2, 19261,629,044 Morter May 17, 1927 1,849,411 Silva et al Mar. 15, 19321,863,920 Costa June 21, 1932

